Abstract

Background

The management of the health of urban lake systems is often reactive and is instigated
in response to poor aesthetic quality or physicochemical measurements, rather than
from an overall assessment of ecosystem health. Interpreting physicochemical monitoring
data in isolation is problematic for two main reasons: the suite of parameters that
are monitored may be limited; and the contribution that any single parameter has towards
water quality or health varies considerably depending on the nature of the system
of interest. Extending monitoring programs to include flora and fauna results in a
better dataset of ecosystem status, but also increases the complexity in interpreting
whether the status is good or poor.

Results

This paper details a process by which a large set of quantitative biological, physical,
chemical and social indicators may be transformed into a simple, but informative,
numerical index that represents the overall ecosystem health, while also identifying
the likely source and scale of pressure for remedial management action. The flexibility
of the proposed approach means that it can be readily adapted to other lake systems
and environments, or even to include or exclude different indicators. A case study
is presented in which the model is used to assess a comprehensive longitudinal dataset
that resulted from monitoring a constructed urban lake in Southeast Queensland, Australia.

Conclusions

The sensitivity analysis and case study indicate that the model identifies how changes
in individual monitoring parameters result in changes in overall ecosystem health,
and thus illustrates its potential as a lake management tool.